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Background: Calcific aortic valve stenosis (CAVS) is a frequent and life-threatening cardiovascular disease for which there is currently no medical treatment available. To date, only 2 genes, LPA and PALMD , have been identified as causal for CAVS. We aimed to identify additional susceptibility genes for CAVS., Methods: A GWAS (genome-wide association study) meta-analysis of 4 cohorts, totaling 5115 cases and 354 072 controls of European descent, was performed. A TWAS (transcriptome-wide association study) was completed to integrate transcriptomic data from 233 human aortic valves. A series of post-GWAS analyses were performed, including fine-mapping, colocalization, phenome-wide association studies, pathway, and tissue enrichment as well as genetic correlation with cardiovascular traits., Results: In the GWAS meta-analysis, 4 loci achieved genome-wide significance, including 2 new loci: IL6 (interleukin 6) on 7p15.3 and ALPL (alkaline phosphatase) on 1p36.12. A TWAS integrating gene expression from 233 human aortic valves identified NAV1 (neuron navigator 1) on 1q32.1 as a new candidate causal gene. The CAVS risk alleles were associated with higher mRNA expression of NAV1 in valve tissues. Fine-mapping identified rs1800795 as the most likely causal variant in the IL6 locus. The signal identified colocalizes with the expression of the IL6 RNA antisense in various tissues. Phenome-wide association analyses in the UK Biobank showed colocalized associations between the risk allele at the IL6 lead variant and higher eosinophil count, pulse pressure, systolic blood pressure, and carotid artery procedures, implicating modulation of the IL6 pathways. The risk allele at the NAV1 lead variant colocalized with higher pulse pressure and higher prevalence of carotid artery stenosis. Association results at the genome-wide scale indicated genetic correlation between CAVS, coronary artery disease, and cardiovascular risk factors., Conclusions: Our study implicates 3 new genetic loci in CAVS pathogenesis, which constitute novel targets for the development of therapeutic agents.

Rationale: Drug-induced valvular heart disease (DI-VHD) remains an under-recognized entity., Patient Concerns: This report describes a heart valve replacement which was complicated by intractable systemic pulmonary arterial hypertension in a 61-year-old female with severe restrictive mitral and aortic disease. The diagnosis of valvular disease was preceded by a history of unexplained respiratory distress. The patient had been exposed to benfluorex for 6.5 years., Diagnoses: The diagnostic procedure documented specific drug-induced valvular fibrosis., Interventions: Surgical mitral and aortic valve replacement was performed., Outcomes: Heart valve replacement was postoperatively complicated by unanticipated disproportionate pulmonary hypertension. This issue was fatal despite intensive care including prolonged extracorporeal life support., Lessons: Benfluorex is a fenfluramine derivative which has been marketed between 1976 and 2009. Although norfenfluramine is the common active and toxic metabolite of all fenfluramine derivatives, the valvular and pulmonary arterial toxicity of benfluorex was much less known than that of fenfluramine and dexfenfluramine. The vast majority of benfluorex-induced valvular heart disease remains misdiagnosed as hypothetical rheumatic fever due to similarities between both etiologies. Better recognition of DI-VHD is likely to improve patient outcome., Competing Interests: The authors have no conflicts of interest to disclose.

Objective: Notch3, a member of the evolutionary conserved Notch receptor family, is primarily expressed in vascular smooth muscle cells. Genetic studies in human and mice revealed a critical role for Notch3 in the structural integrity of distal resistance arteries by regulating arterial differentiation and postnatal maturation., Methods and Results: We investigated the role of Notch3 in vascular tone in small resistance vessels (tail and cerebral arteries) and large (carotid) arteries isolated from Notch3-deficient mice using arteriography. Passive diameter and compliance were unaltered in mutant arteries. Similarly, contractions to phenylephrine, KCl, angiotensin II, and thromboxane A2 as well as dilation to acetylcholine or sodium nitroprusside were unaffected. However, Notch3 deficiency induced a dramatic reduction in pressure-induced myogenic tone associated with a higher flow (shear stress)-mediated dilation in tail and cerebral resistance arteries only. Furthermore, RhoA activity and myosin light chain phosphorylation, measured in pressurized tail arteries, were significantly reduced in Notch3KO mice. Additionally, myogenic tone inhibition by the Rho kinase inhibitor Y27632 was attenuated in mutant tail arteries., Conclusions: Notch3 plays an important role in the control of vascular mechano-transduction, by modulating the RhoA/Rho kinase pathway, with opposite effects on myogenic tone and flow-mediated dilation in the resistance circulation.